- ID:
- ivo://CDS.VizieR/J/MNRAS/404/1719
- Title:
- Combined NVSS-FIRST galaxies (CoNFIG) sample II
- Short Name:
- J/MNRAS/404/1719
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper focuses on a comparison of the space densities of Fanaroff-Riley type I (FR I) and FR II sources at different epochs, with a particular focus on FR I sources. First, we present the concluding steps in constructing the Combined NVSS-FIRST Galaxies (CoNFIG) catalogue, including new Very Large Array observations, optical identifications and redshift estimates. The final catalogue consists of 859 sources over four samples (CoNFIG-1, -2, -3 and -4 with flux density limits of S1.4GHz=1.3, 0.8, 0.2 and 0.05Jy, respectively). It is 95.7 per cent complete in radio morphology classification and 74.3 per cent of the sources have redshift data. Combining CoNFIG with complementary samples, the distribution and evolution of FR I and FR II sources are investigated. We find that FR I sources undergo mild evolution and that, at the same radio luminosity, FR I and FR II sources show similar space density enhancements in various redshift ranges, possibly implying a common evolution.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/744/84
- Title:
- Combined sample of radio-loud AGNs at 408MHz
- Short Name:
- J/ApJ/744/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The work in this paper aims at determining the evolution and possible co-evolution of radio-loud active galactic nuclei (AGNs) and their cores via their radio luminosity functions (i.e., total and core RLFs, respectively). Using a large combined sample of 1063 radio-loud AGNs selected at low radio frequency, we investigate the RLF (radio luminosity function) at 408MHz of steep-spectrum radio sources. Our results support a luminosity-dependent evolution. Using core flux density data of the complete sample 3CRR (Laing et al., 1983, Cat. J/MNRAS/204/151; see also Cat. VIII/1), we investigate the core RLF at 5.0GHz. Based on the combined sample with incomplete core flux data, we also estimate the core RLF using a modified factor of completeness. Both results are consistent and show that the comoving number density of radio cores displays a persistent decline with redshift, implying a negative density evolution. We find that the core RLF is obviously different from the total RLF at the 408 MHz band which is mainly contributed by extended lobes, implying that the cores and extended lobes could not be co-evolving at radio emission.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A39
- Title:
- Cometary HII regions of DR21
- Short Name:
- J/A+A/563/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep Very Large Array H66{alpha} radio recombination line (RRL) observations of the two cometary HII regions in DR 21. With these sensitive data, we test the "hybrid" bow shock/champagne flow model previously proposed for the DR 21 HII regions.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A127
- Title:
- Comet C/2016 R2 (PanSTARRS) IRAM spectra
- Short Name:
- J/A+A/619/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-wavelength study of comet C/2016 R2 (PanSTARRS). This comet was observed on 23-24 January 2018 with the IRAM 30m telescope, and in January to March 2018 with the Nancay radio telescope. Visible spectroscopy was performed in December 2017 and February 2018 with small amateur telescopes. We report on measurements of CO, CH_3_OH, H_2_CO and HCN production rates, and on the determination of the N2/CO abundance ratio. Several other species, especially OH, were searched for but not detected. The inferred relative abundances, including upper limits for sulfur species, are compared to those measured in other comets at about the same heliocentric distance of ~2.8AU. The coma composition of comet C/2016 R2 is very different from all other comets observed so far, being rich in N2 and CO and dust poor. This suggests that this comet might belong to a very rare group of comets formed beyond the N_2_ ice line. Alternatively, comet C/2016 R2 (PanSTARRS) could be the fragment of a large and differentiated transneptunian object, with properties characteristic of volatile-enriched layers.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A49
- Title:
- Comet 46P/Wirtanen millimetre-wave spectra
- Short Name:
- J/A+A/648/A49
- Date:
- 08 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of a molecular survey of comet 46P/Wirtanen undertaken with the IRAM 30-m and NOEMA radio telescopes in December 2018. Observations at IRAM 30-m during the 12-18 Dec. period comprise a 2mm spectral survey, which covers 25GHz, and a 1mm survey which covers 62GHz. The gas outflow velocity and kinetic temperature have been accurately constrained by the observations. We derive abundances of 11 molecules, some being identified remotely for the first time in a Jupiter-family comet, including complex organic molecules such as formamide, ethylene glycol, acetaldehyde or ethanol. Sensitive upper limits on the abundances of 24 other molecules are obtained. The comet is found to be relatively rich in methanol (3.4% relative to water) but relatively depleted in CO, CS, HNC, HNCO or HCOOH.
- ID:
- ivo://CDS.VizieR/J/PASJ/60/1297
- Title:
- CO molecular clouds in Carina flare supershell
- Short Name:
- J/PASJ/60/1297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of ^12^CO(J=1-0) and ^13^CO(J=1-0) molecular clouds in the spatio-velocity range of the Carina Flare supershell, GSH287+04-17. The data cover a region of ~66 square degrees and were taken with the NANTEN 4m telescope, at spatial and velocity resolutions of ~2.6' and 0.1km/s. Decomposition of the emission results in the identification of 156 ^12^CO clouds and 60 ^13^CO clouds, for which we provide observational and physical parameters.
- ID:
- ivo://CDS.VizieR/J/PASJ/57/917
- Title:
- CO molecular clouds in southern Galactic Warp
- Short Name:
- J/PASJ/57/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made an unbiased search for molecular clouds in the Galactic Warp. This survey, covering an area of 56 square degrees at l=252{deg} to 266{deg} and b=-5{deg} to -1{deg}, revealed 70 molecular clouds, while only 6 clouds were previously known in this sector at R>~14.5kpc.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/57
- Title:
- Compact bright radio-loud AGNs. III. VLBA 43GHz
- Short Name:
- J/ApJS/247/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from the 43GHz Very Long Baseline Array (VLBA) observations of 124 compact radio-loud active galactic nuclei (AGNs) that were conducted between 2014 November and 2016 May. The typical dimensions of the restoring beam in each image are about 0.5masx0.2mas. The highest resolution of 0.2mas corresponds to a physical size of 0.02pc for the lowest redshift source in the sample. The 43GHz very long baseline interferometry (VLBI) images of 97 AGNs are presented for the first time. We study the source compactness on milliarcsecond and submilliarcsecond scales, and suggest that 95 sources in our sample are suitable for future space VLBI observations. By analyzing our data supplemented with other VLBA AGN surveys from the literature, we find that the core brightness temperature increases with increasing frequency below a break frequency ~7GHz, and decreases between ~7 and 240GHz but increases again above 240GHz in the rest frame of the sources. This indicates that the synchrotron opacity changes from optically thick to thin. We also find a strong statistical correlation between radio and {gamma}-ray flux densities. Our correlation is tighter than those in the literature derived from lower-frequency VLBI data, suggesting that the {gamma}-ray emission is produced more cospatially with the 43GHz VLBA core emission. This correlation can also be extrapolated to the unbeamed AGN population, implying that a universal {gamma}-ray production mechanism might be at work for all types of AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJS/145/83
- Title:
- Compact radio sources at -30<Dec<0
- Short Name:
- J/ApJS/145/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 321 compact radio sources in the declination range 0{deg}>{delta}>-30{deg}. The positions of these sources have been measured with a two-dimensional rms accuracy of 35milliarcseconds using the NRAO Very Large Array. Each source has a peak flux density >50mJy at 8.4GHz. We intend for this catalog to be used mainly for selection of phase calibration sources for radio interferometers, although compact radio sources have other scientific uses.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/325
- Title:
- Compact Radio Sources in & behind LMC catalogue
- Short Name:
- J/A+AS/126/325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a continuum snapshot survey of a 3x4{deg}^2^ region of the Large Magellanic Cloud including the area of the giant molecular cloud and the 30 Doradus nebula. The observations have been carried out with the Australia Telescope Compact Array (ATCA) at 1.4 and 2.4GHz. Most fields are complete to about 6mJy peak flux density at 1.4GHz and to about 3mJy at 2.4GHz. The positions, peak and integral flux densities of 113 compact (<54") sources detected at 1.4GHz and of 70 sources (<34") detected at 2.4GHz are presented. Positions are accurate to about 3" and peak flux densities are accurate to about 10% or better, depending on the source position relative to the pointing centers. 32 of the sources detected at 1.4GHz are coincident with H{alpha} objects in the catalogue of Davies, Elliot and Meaburn (1976MmRAS..81...89D); these are possibly intrinsic to the LMC. However, we suppose that most are background objects, since the number vs. flux agrees with predictions of extragalactic source counts from other surveys.